The Experts below are selected from a list of 288894 Experts worldwide ranked by ideXlab platform
Toshinori Fujii - One of the best experts on this subject based on the ideXlab platform.
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A Simulator of Superconducting Magnetic Energy Storage and an Experiment of Levelling Load Power Fluctuation
IEEJ Transactions on Industry Applications, 1998Co-Authors: Shigeyuki Funabiki, Tsuyoshi Yorioka, Toshinori FujiiAbstract:A Superconducting Magnetic Energy Storage (SMES) using superconductive coil is effective Power storage system. An electric Power system using SMES can perform levelling Load Power fluctuation and improve the, stability of Power system. It is impossible to examine a control strategy for levelling Load Power fluctuation using a SMES, because we can not realize a large capacity of SMES. So we build a SMES simulator as a trial that operates coordinately as a superconductive coil.In this paper, a superconductive coil composed of a coil and a inverter curcuit is realized by numerical expression and experiment. The contorol strategy based on an auto-tuning of scailing factors with neural network can realize levelling the fluctuating active Power and compensating the reactive Power using the SMES simulator.
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A Control Strategy of Leveling Load Power Fluctuation by Successive Learning Fuzzy-Neural Network Based on Prediction of Average Load Power
IEEJ Transactions on Industry Applications, 1996Co-Authors: Toshinori Fujii, Shigeyuki FunabikiAbstract:The effective usage of the Power facilities can be realized by leveling the fluctuating active Power and compensating the reactive Power. The fuzzy control strategy of superconducting magnet energy storages (SMES) was proposed for this purpose. The control results depend on the values of scaling factors in fuzzy reasoning. Therefore, it is desired to obtain better control results that the scaling factors are successively adjusted according to the Load Power fluctuation.In this paper, the control strategy based on an auto-tuning of scaling factors and a fuzzy singleton-type of reasoning method using the back propagation of neural network is proposed for leveling Load fluctuation. The prediction and revision of teaching signal with energy of SMES is proposed. The coefficients of learning rate and the revision of the teaching signal is discussed. Then, we can achieve the better leveling of Load Power fluctuation by using fuzzy logic and neural network.
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Fuzzy control of SMES for levelling Load Power fluctuation based on Lukasiewicz logic
IEE Proceedings C Generation Transmission and Distribution, 1993Co-Authors: Shigeyuki Funabiki, Toshinori FujiiAbstract:Provided that superconducting magnetic energy storage (SMES) is located near the consumer in the Power system, levelling of fluctuating Load Power and compensation of reactive Power can be achieved. Thus, loss in the Power system can be reduced and the Power system stability can be improved. In this paper, an SMES control strategy for levelling the fluctuating Load Power based on Lukasiewicz logic is proposed. The control characteristics are discussed by comparing a simulation with the control results of other methods proposed by the authors. The variance achieved by the proposed method is smaller than those obtained with the other control methods. Thus, the proposed control method is superior to other control methods.
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A Control Strategy of Levelling Load Power Fluctuation by Using Superconducting Magnetic Energy Storge
IEEJ Transactions on Industry Applications, 1991Co-Authors: Shigeyuki Funabiki, Toshinori FujiiAbstract:If a small capacity of superconducting magnetic energy storaga (SMES) is developed, it can be expected that the SMES equipped near to the consumer levels the Load Power fluctuation and compensates the reactive Power rapidly. It leads the effective use of the Power facilities. In this paper, the authors propose the control strategy of the SMES for levelling the Load Power fluctuation and compensating the reactive Power. Then, the validity of the proposed method is discussed by simulation, The obtained results are summarized as follows.(1) The control method of the SMES is proposed with the estimation function taking account of the energy stored in the SMES and the levelling of Load Power fluctration.(2) The region of the proper weighting factors of the estimation function and the exponential smoothing method are obaained for the Load Power fluctuation. The levelling of the Power following the sustained component of the Load Power fluctuation can be achieved by using the obtained weighting factors.(3) The effects of the energy capacity and the current ratings of the SMES on the levelling of the Load Power fluctuation and the compensation of the reactive Power are clarified.
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A Control Strategy Based on Fuzzy Logic for Levelling Load Power Fluctuation by Using Superconducting Magnetic Energy Storage
IEEJ Transactions on Industry Applications, 1991Co-Authors: Shigeyuki Funabiki, Toshinori FujiiAbstract:The control strategy based on fuzzy logic is proposed for levelling the Load Power fluctuation and compensating the reactive Power by using the superconducting magnetic energy storage (SMES) equipped near to the consumer. Then, its control effects are discussed by simulation. The obtained results are summarized as follows.(1) The conditions with respect to the levelling of the active Power in the source line and the energy stored in the SMES are introduced. Then, the production rules on these conditions are constructed.(2) The estimation value LD of levelling the active Power in the source line is proposed in addition to the estimation value υ of following the sustained component.(3) Provided that the base of the triangle in the menbership function is set to 1.05 for the Load Power fluctuation investigated, the most preferable result can be obtained when the heights of triange are 0.01 and 0.6 in the rule 1 and the rule 2, respectively.(4) Comparing with the control results by using the estimation function, the estimation value υ with the fuzzy control is less than that with the estimation function regardless of the capacity of the SMES. Therefore, it is clarified that the levelling of Load Power fluctuation can be achieved by the fuzzy control better than by the estimation function.
Ian Dobson - One of the best experts on this subject based on the ideXlab platform.
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new methods for computing a closest saddle node bifurcation and worst case Load Power margin for voltage collapse
IEEE Transactions on Power Systems, 1993Co-Authors: Ian Dobson, L LuAbstract:Voltage collapse and blackout can occur in an electric Power system when Load Powers vary so that the system loses stability in a saddle node bifurcation. The authors propose new iterative and direct methods to compute Load Powers at which bifurcation occurs and which are locally closest to the current operating Load Powers. The distance in Load Power parameter space to this locally closest bifurcation is an index of voltage collapse. The pattern of Load Power increase need not be predicted; instead the index is a worst case Load Power margin. The computations are illustrated in the six-dimensional Load Power parameter space of a five bus Power system. The normal vector and curvature of a hypersurface of critical Load Powers at which bifurcation occurs are also computed. The sensitivity of the index to parameters and controls is easily obtained from the normal vector. >
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A direct method for computing a closest saddle node bifurcation in the Load Power parameter space of an electric Power system
1991. IEEE International Sympoisum on Circuits and Systems, 1Co-Authors: Ian DobsonAbstract:Voltage collapse and blackout can occur in an electric Power system when Load Powers vary so that the system loses stability in a saddle node bifurcation. A direct method is presented to compute the Load Powers at which bifurcation occurs and which are locally closest to the current operating Load Powers. The computation is illustrated in the 6-dimensional Load Power parameter space of a 5 bus Power system. >
L Lu - One of the best experts on this subject based on the ideXlab platform.
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new methods for computing a closest saddle node bifurcation and worst case Load Power margin for voltage collapse
IEEE Transactions on Power Systems, 1993Co-Authors: Ian Dobson, L LuAbstract:Voltage collapse and blackout can occur in an electric Power system when Load Powers vary so that the system loses stability in a saddle node bifurcation. The authors propose new iterative and direct methods to compute Load Powers at which bifurcation occurs and which are locally closest to the current operating Load Powers. The distance in Load Power parameter space to this locally closest bifurcation is an index of voltage collapse. The pattern of Load Power increase need not be predicted; instead the index is a worst case Load Power margin. The computations are illustrated in the six-dimensional Load Power parameter space of a five bus Power system. The normal vector and curvature of a hypersurface of critical Load Powers at which bifurcation occurs are also computed. The sensitivity of the index to parameters and controls is easily obtained from the normal vector. >
Shigeyuki Funabiki - One of the best experts on this subject based on the ideXlab platform.
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A Simulator of Superconducting Magnetic Energy Storage and an Experiment of Levelling Load Power Fluctuation
IEEJ Transactions on Industry Applications, 1998Co-Authors: Shigeyuki Funabiki, Tsuyoshi Yorioka, Toshinori FujiiAbstract:A Superconducting Magnetic Energy Storage (SMES) using superconductive coil is effective Power storage system. An electric Power system using SMES can perform levelling Load Power fluctuation and improve the, stability of Power system. It is impossible to examine a control strategy for levelling Load Power fluctuation using a SMES, because we can not realize a large capacity of SMES. So we build a SMES simulator as a trial that operates coordinately as a superconductive coil.In this paper, a superconductive coil composed of a coil and a inverter curcuit is realized by numerical expression and experiment. The contorol strategy based on an auto-tuning of scailing factors with neural network can realize levelling the fluctuating active Power and compensating the reactive Power using the SMES simulator.
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A Control Strategy of Leveling Load Power Fluctuation by Successive Learning Fuzzy-Neural Network Based on Prediction of Average Load Power
IEEJ Transactions on Industry Applications, 1996Co-Authors: Toshinori Fujii, Shigeyuki FunabikiAbstract:The effective usage of the Power facilities can be realized by leveling the fluctuating active Power and compensating the reactive Power. The fuzzy control strategy of superconducting magnet energy storages (SMES) was proposed for this purpose. The control results depend on the values of scaling factors in fuzzy reasoning. Therefore, it is desired to obtain better control results that the scaling factors are successively adjusted according to the Load Power fluctuation.In this paper, the control strategy based on an auto-tuning of scaling factors and a fuzzy singleton-type of reasoning method using the back propagation of neural network is proposed for leveling Load fluctuation. The prediction and revision of teaching signal with energy of SMES is proposed. The coefficients of learning rate and the revision of the teaching signal is discussed. Then, we can achieve the better leveling of Load Power fluctuation by using fuzzy logic and neural network.
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Fuzzy control of SMES for levelling Load Power fluctuation based on Lukasiewicz logic
IEE Proceedings C Generation Transmission and Distribution, 1993Co-Authors: Shigeyuki Funabiki, Toshinori FujiiAbstract:Provided that superconducting magnetic energy storage (SMES) is located near the consumer in the Power system, levelling of fluctuating Load Power and compensation of reactive Power can be achieved. Thus, loss in the Power system can be reduced and the Power system stability can be improved. In this paper, an SMES control strategy for levelling the fluctuating Load Power based on Lukasiewicz logic is proposed. The control characteristics are discussed by comparing a simulation with the control results of other methods proposed by the authors. The variance achieved by the proposed method is smaller than those obtained with the other control methods. Thus, the proposed control method is superior to other control methods.
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A Control Strategy of Levelling Load Power Fluctuation by Using Superconducting Magnetic Energy Storge
IEEJ Transactions on Industry Applications, 1991Co-Authors: Shigeyuki Funabiki, Toshinori FujiiAbstract:If a small capacity of superconducting magnetic energy storaga (SMES) is developed, it can be expected that the SMES equipped near to the consumer levels the Load Power fluctuation and compensates the reactive Power rapidly. It leads the effective use of the Power facilities. In this paper, the authors propose the control strategy of the SMES for levelling the Load Power fluctuation and compensating the reactive Power. Then, the validity of the proposed method is discussed by simulation, The obtained results are summarized as follows.(1) The control method of the SMES is proposed with the estimation function taking account of the energy stored in the SMES and the levelling of Load Power fluctration.(2) The region of the proper weighting factors of the estimation function and the exponential smoothing method are obaained for the Load Power fluctuation. The levelling of the Power following the sustained component of the Load Power fluctuation can be achieved by using the obtained weighting factors.(3) The effects of the energy capacity and the current ratings of the SMES on the levelling of the Load Power fluctuation and the compensation of the reactive Power are clarified.
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A Control Strategy Based on Fuzzy Logic for Levelling Load Power Fluctuation by Using Superconducting Magnetic Energy Storage
IEEJ Transactions on Industry Applications, 1991Co-Authors: Shigeyuki Funabiki, Toshinori FujiiAbstract:The control strategy based on fuzzy logic is proposed for levelling the Load Power fluctuation and compensating the reactive Power by using the superconducting magnetic energy storage (SMES) equipped near to the consumer. Then, its control effects are discussed by simulation. The obtained results are summarized as follows.(1) The conditions with respect to the levelling of the active Power in the source line and the energy stored in the SMES are introduced. Then, the production rules on these conditions are constructed.(2) The estimation value LD of levelling the active Power in the source line is proposed in addition to the estimation value υ of following the sustained component.(3) Provided that the base of the triangle in the menbership function is set to 1.05 for the Load Power fluctuation investigated, the most preferable result can be obtained when the heights of triange are 0.01 and 0.6 in the rule 1 and the rule 2, respectively.(4) Comparing with the control results by using the estimation function, the estimation value υ with the fuzzy control is less than that with the estimation function regardless of the capacity of the SMES. Therefore, it is clarified that the levelling of Load Power fluctuation can be achieved by the fuzzy control better than by the estimation function.
Hong-hee Lee - One of the best experts on this subject based on the ideXlab platform.
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a Power distributed control method for proportional Load Power sharing and bus voltage restoration in a dc microgrid
IEEE Transactions on Industry Applications, 2018Co-Authors: Duy-hung Dam, Hong-hee LeeAbstract:This paper proposes a new Power distributed control method for a dc microgrid. This method was developed to share the Load Power proportionally to the distributed Power source ratings and restore the dc bus voltage when the Load changes. To achieve this effectively, a shifted voltage technique was developed based on the Power rating and the instantaneous Power of distributed generators. By adding the shifted voltage, the voltage drop caused by the droop controller is effectively compensated such that the dc bus voltage is constantly regulated regardless of the Load change. To realize the method, all the required information to determine the reference voltage is transmitted through low-bandwidth communication. The controller design process is presented in detail along with a system stability analysis. The effectiveness of the method was verified by simulation and experiments, which were carried out using a 2.8-kW prototype of a dc microgrid.
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An adaptive Power distributed control method to ensure proportional Load Power sharing in DC microgrid considering equivalent line impedances
2016 IEEE Energy Conversion Congress and Exposition (ECCE), 2016Co-Authors: Duy-hung Dam, Hong-hee LeeAbstract:This paper proposed a distributed control method for dc microgrid to ensure the proportional Load sharing by taking into account the different line impedance. In the proposed method, the operation point of each DG is effectively defined based on the Power rating and the instantaneous Power of the DG to achieve the proportional Load Power sharing. A low bandwidth communication is used to transmit the data required to determine the Power reference for all DGs. In order to balance the Power per unit requirement, the output voltage of each DG is controlled by a Power controller to adjust the desired operating point. Therefore, all DGs can operate at the balanced operating point on the droop curve to ensure the proportional Load Power sharing. This paper also considers the Load shedding to prevent the dc microgrid from operating under overLoad condition. The effectiveness of the proposed method is verified by simulation and experiment which are carried out with 2.8kW prototype dc microgrid.
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Optimized Discontinuous PWM Algorithm With Variable Load Power Factor For Multilevel Inverters
37th IEEE Power Electronics Specialists Conference, 1Co-Authors: Nguyen Van Nho, Hong-hee LeeAbstract:Recently, for multilevel inverters, the various PWM performances can be properly controlled by an offset controller in the carrier based PWM modulator. It has shown a generalised algorithm for realizing a discontinuous PWM technique for defined common mode. For applications with variable Load Power factor, reduction of switching losses can be improved if common mode is properly adjusted to avoid commutation instants at high current amplitudes. In the paper, the problem, how to design a common mode in DPWM for variable Load Power factor will be investigated. A novel carrier PWM algorithm capable of offset control will be presented. The advantage is simple and flexible algorithm. This algorithm will be utilized in designing an optimized discontinuous PWM for variable Load Power factor. The method is mathematically formulated and demonstrated by simulation results.
